Dynamic emergency radiation monitor

ABSTRACT

A dynamic radiation monitor having a detector coupled to a computer to determine at any given location, the amount of time a person has before a pre-selected maximum permissible radiation exposure is received. The device dynamically calculates and outputs the user&#39;s permissible stay time for a given area based on a personalized maximum permissible dose, and adjusts in real time the output based on elapsed time and changing exposure rate. The device also provides the user audio and visual feedback such as varying background colors for different stay time ranges.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from, and is a 35 U.S.C. § 111(a)continuation of, co-pending PCT international application serial numberPCT/US2006/004961 filed on Feb. 9, 2006, incorporated herein byreference in its entirety, which designates the U.S. and which claimspriority from U.S. provisional application Ser. No. 60/652,168 filed onFeb. 10, 2005, incorporated herein by reference in its entirety.

This application is related to U.S. Pat. No. 7,205,544 issued on Apr.17, 2007, incorporated herein by reference in its entirety.

This application is also related to U.S. Patent Application PublicationNo. US 2006/0237648 A1, incorporated herein by reference in itsentirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not Applicable

NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION

A portion of the material in this patent document is subject tocopyright protection under the copyright laws of the United States andof other countries. The owner of the copyright rights has no objectionto the facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the United States Patent andTrademark Office publicly available file or records, but otherwisereserves all copyright rights whatsoever. The copyright owner does nothereby waive any of its rights to have this patent document maintainedin secrecy, including without limitation its rights pursuant to 37C.F.R. § 1.14.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention pertains to a dynamic radiation monitor, and inparticular, a dynamic radiation monitor that determines, at any giventime, the amount of time a person has at a particular location untilreceiving a pre-selected maximum permissible radiation exposure.

2. Description of Related Art

Monitoring radiation levels is advantageous in a number of differentenvironments. For example, in the nuclear power industry, the exposureof people to occupational radiation must be monitored in order toprotect their health. In normal operation, this problem has been solvedwith relatively simple and inexpensive devices.

In other situations such as in the case of a radiation leak whichrequires clean-up operations, or nuclear or dirty bomb detonation, theradiation levels to be encountered are not easily predicted, and theselevels would likely be much higher than those encountered in the morenormal situation. The higher radiation levels mean that an individual'sexposure can rapidly approach safe limits. Therefore, it is important tohave a device capable of calculating and displaying in real time theradiation dose, dose rate, as well as the allowable stay time, inaddition to providing visual and/or audio alarms that are readily andreliably relied to the operator

Radiation monitors which indicate whether a biological organism, such asa person, has been exposed to radiation are well known. For example,U.S. Pat. No. 4,642,463 (Thoms) issued Feb. 10, 1987 and entitledINTELLIGENT RADIATION MONITOR, which is incorporated herein by referencein its entirety, discloses a radiation monitor having a processor anddisplay for detecting and signaling real time radiation rates.

U.S. Pat. No. 5,572,027 (Tawil et al.) issued Nov. 5, 1996 and entitledINTEGRATED DOSIMETER FOR SIMULTANEOUS PASSIVE AND ACTIVE DOSIMETRY,which is incorporated herein by reference in its entirety, discloses aradiation monitoring system using paired active and passive radiationdetectors to monitor radiation exposure. The active detector has aprocessor to monitor the radiation rate and dose level, and has a LCDdisplay for indicating the dose and/or dose rate.

U.S. Pat. No. 6,031,454 (Lovejoy et al.) issued Feb. 29, 2000 andentitled WORKER SPECIFIC EXPOSURE MONITOR AND METHOD OF SURVEILLANCE OFWORKERS, which is incorporated herein by reference in its entirety,discloses a radiation monitor that tracks radiation doses in real time.

The above mentioned devices, however, do not process the detectedradiation data in form that is convenient or desirable to the user. Thevast majority of first responders to a radiation event will likely notbe experts in radiation detection technology or radiation safety. Evenif they have received training, they will likely not remember thesignificance of the various radiation units displayed by currentgeneration meters and dosimeters. These first responders need to be ableto stay focused on their area of expertise (e.g., fire-fighting, rescueoperations, emergency medical treatment, crowd control, forensics,etc.). When responding to the scene, the following factors are generallyof paramount interest to the responder: radiation levels with respect tonormal background, time left to work safely; safety of some locationswith respect to others, significant changes in the radiation hazardenvironment, and when to leave the area.

Therefore, an objective of the present invention is to provide areal-time radiation monitor that is programmable to allow for quick andidentifiable communication of critical information that is of interestto the responder.

BRIEF SUMMARY OF THE INVENTION

An aspect of the invention is a personal radiation monitor having adetector configured for producing real time radiation exposure data, anda processor responsive to the detector and configured for calculatingone or more characteristics of an individual's radiation exposure. Theprocessor is configured to continuously recalculate said radiationexposure data to update the radiation exposure characteristics, suchthat a display responsive to information provided by the processor. Thedisplay is adapted to display at least one of the radiation exposurecharacteristics as a primary signal from said processor. The processoris further configured to transmit a secondary signal to the individual,wherein the secondary signal correlates to a range of values of one ofthe radiation exposure characteristics.

In one embodiment, the display comprises an illuminated background thatis responsive to the secondary signal, wherein the illuminatedbackground color is configured to change color upon the radiationexposure characteristic exceeding a threshold limit outside the range ofvalues. The display background may be further configured to illuminate afirst color upon a radiation exposure characteristic falling within afirst range of values, a second color upon a radiation exposurecharacteristic falling within a second range of values, and a thirdcolor upon a radiation exposure characteristic falling within a thirdrange of values. The display background may also be configured to flashthe third color upon a radiation exposure characteristic falling withina fourth range of values.

In one variation of the current embodiment, the processor is furtherconfigured to transmit a tertiary signal to the individual, wherein thetertiary signal comprises an audio signal having a rate associated withthe range of values, and wherein the audio signal rate is configured tochange upon one of the one or more radiation exposure characteristicsexceeding a threshold limit outside the range of values.

In an alternative embodiment, the monitor may have one or moreillumination sources in proximity to the display, wherein theillumination sources are responsive to the secondary signal so as tocommunicate one or more radiation exposure characteristics exceeding athreshold limit outside the range of values.

In yet another alternative embodiment, the secondary signal comprises anaudio signal having a rate associated with the range of values, whereinthe audio signal rate is configured to change upon one of the one ormore radiation exposure characteristics exceeding a threshold limitoutside the range of values.

The radiation exposure characteristics may comprise a number ofindications, including accumulative radiation exposure level, radiationdose rate, and a stay time based on the individual's maximum permissibleradiation dose limit, wherein the processor is configured tocontinuously recalculate the stay time to accommodate for theaccumulative exposure level or changing radiation dose rates. Thebackground color of the display may further be configured to changecolor when the stay time exceeds a threshold limit outside the range ofvalues.

In another embodiment, the processor is configured to output the staytime to the display during a display time interval, wherein the displaytime interval locks the value of the display for a specified period oftime. In addition to, or as an alternative to the display time interval,the processor may be configured to average the radiation dose rate overa period of time to stabilize the display of the stay time influctuating radiation exposure environments.

In another preferred embodiment, the display is configured to displaytwo or more of either the radiation dose rate, accumulative dose, orstay time simultaneously. In addition, the display may be configured todisplay one of the radiation exposure characteristics as a primaryreadout, and the remaining radiation exposure characteristics aresimultaneously displayed on a status meter.

The monitor may also comprise a plurality of controls coupled to theprocessor, wherein the controls are configured to allow parameters ofthe radiation exposure characteristics to be pre-programmed by theindividual. The controls may also be configured to allow the primaryreadout to be toggled between the one or more radiation exposurecharacteristics.

In another embodiment, the display is further configured to transmit apre-programmed text message upon a specified radiation exposurecharacteristic value, such as stay time, dose rate, or cumulative dose.

Another aspect of the invention is a personal radiation monitor, havinga detector configured for producing real time radiation exposure data,and a processor responsive to the detector and configured forcalculating a stay time based on an individual's maximum permissibleradiation dose limit, the processor further configured for continuouslyrecalculating the stay time based on the individual's accumulatedexposure and radiation exposure rate. The monitor further comprises adisplay responsive to information provided by the processor, wherein thedisplay is adapted for displaying at least the stay time data from theprocessor, and has a variable background that changes color based onchanges in the stay time data.

In a preferred embodiment of the current aspect, the display exhibits afirst color for a stay time greater than a first time period, a secondcolor for a stay time less than a second time period, and a third colorfor a stay time less than a third time period.

In another embodiment, the processor may further configured to transmitan audio signal to the individual, wherein the audio signal has a rateassociated with the stay time that changes in the stay time data.

The monitor may further include a plurality of controls coupled to theprocessor, wherein the controls are configured to allow parameters ofthe maximum permissible exposure, stay time, accumulated exposure andradiation exposure rate to be pre-programmed by the individual.

A further aspect of the invention is a method of monitoring radiationexposure levels. The method includes the steps of inputting anindividual's maximum permissible radiation dose limit, detectingradiation exposure levels at a location at or near the individual,calculating a stay time as a function of the detected radiation exposurelevels and the maximum permissible radiation dose limit, and displayingthe stay time against an illuminated background. The method furtherincludes the steps of continuously recalculating the stay time accordingto the individual's detected accumulated exposure and radiation exposurerate, updating the display of the stay time, and changing the backgroundcolor in response to the stay time falling outside a predetermined rangeof values.

In a preferred embodiment of the current aspect, changing the backgroundcolor comprises illuminating a first color for a stay time greater thana first time period, illuminating a second color for a stay time lessthan a second time period, and illuminating a third color for a staytime less than a third time period. In addition a third color may beflashed in response to the stay time having a value less than a fourthtime period.

The method may further include transmitting an audio signal to theindividual, wherein the audio signal has a rate associated with the staytime that changes upon the value of the stay time.

In a preferred embodiment, the individual's stay time, accumulatedexposure and radiation exposure rate are displayed simultaneously.

Further aspects of the invention will be brought out in the followingportions of the specification, wherein the detailed description is forthe purpose of fully disclosing preferred embodiments of the inventionwithout placing limitations thereon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The invention will be more fully understood by reference to thefollowing drawings which are for illustrative purposes only:

FIG. 1 is an embodiment of a portable radiation monitor in accordancewith the present invention.

FIG. 2 is a side view of the portable radiation monitor of FIG. 1

FIG. 3 is a schematic view of the components of a portable radiationmonitor such as that shown in FIG. 1.

FIG. 4 illustrates an exemplary display readout of the radiation monitorof the present invention, with a primary readout showing stay timeremaining.

FIG. 5 illustrates another exemplary display readout of the radiationmonitor of the present invention.

FIG. 6 shows yet another display readout of the radiation monitor of thepresent invention.

FIG. 7 illustrates another exemplary display readout of the radiationmonitor of the present invention.

FIG. 8 illustrates an exemplary display readout of the radiation monitorof the present invention, with a primary readout showing the dose rate.

FIG. 9 illustrates an exemplary display readout of the radiation monitorof the present invention, with a primary readout showing the totalaccumulated dose.

FIG. 10 illustrates an alternative configuration of the radiationmonitor of the present invention, with an additional LED statusindicators.

FIG. 11 shows another alternative configuration of the radiation monitorof the present invention, with numeric status meters and a programmedtext message.

FIG. 12 illustrates an exemplary context sensitive PC pull down menu inaccordance with the present invention.

FIG. 13. illustrates exemplary pull-down options for the menu of FIG.12.

DETAILED DESCRIPTION OF THE INVENTION

Referring more specifically to the drawings, for illustrative purposesthe present invention is embodied in the apparatus generally shown inFIG. 1 through FIG. 13. It will be appreciated that the apparatus mayvary as to configuration and as to details of the parts, and that themethod may vary as to the specific steps and sequence, without departingfrom the basic concepts as disclosed herein.

The present invention pertains to a dynamic radiation monitor/dosimeterhaving a detector coupled to a computer/processor to determine, at anygiven location, the amount of time a person has before a pre-selectedmaximum permissible radiation exposure is received. In general terms,the monitor dynamically calculates and outputs the user's permissiblestay time for a given area based on a personalized maximum permissibledose, and adjusts in real time the output based on changes in exposurerate at any given location, accumulated dose, and elapsed time. Themonitor also provides the user audio and visual feedback such as varyingbackground colors for different stay time ranges.

More particularly, the purpose of radiation monitor of the presentinvention is to provide emergency response personnel (Fire, Police,HAZMAT) with dynamic, continual real time updates on how long they cansafely remain in a radiation area when responding to an accident orterrorist event involving radiation.

The device and methods of the present invention greatly simplify theinformation given to the responder and provides the critical data neededto answer critical questions, such as: “How long can I safely stayhere?” Or, “If I move the patient back two feet, how much more time willI have?”

Referring to FIGS. 1 and 2, a radiation monitor 10 in accordance withthe present invention is illustrated.

Externally, the monitor 10 comprises a housing 12 having a display 14,speaker 26, and plurality of control buttons. For example, a pluralityof arrow buttons 16 may be used to control the on-screen display in a“set-up” mode for assigning the desired user variables and parameters.Alternatively, a single arrow button may be provided in compassconfiguration. The device may also have an “enter (E)” button 18 forselecting menu functions and for entering “set up” mode (e.g. bypressing button 18 for 5 seconds to initiate the set-up menu out of alocked configuration).

The mode (M) button 24 is used for toggling between display options,such as time, dose rate, total dose etc. To save battery life, thedevice may have an on/off button 22 for powering up/down the unit. Themode (M) button 24 may also be context sensitive. For example, when thedevice is displaying an alarm, the M button may be pressed to stop or“acknowledged” the alarm. The same may occur when any alarm or messagewas displayed. After the message or alarm was acknowledged, the M buttonwould revert to its display mode function.

The monitor 10 may also have audio controls such as volume (+) or (−)buttons 20 to change the output of the signal to the speakers. Volume(+) or (−) buttons 20 may also be used to change the display brightnessin other modes. Where it is desired to have the device operate insilence, the monitor 10 may also include a mute or toggle 28 for thetone alarm.

Referring to FIG. 2, housing 12 may also support components accessiblefrom the side of the radiation monitor 10, e.g. input port 40. Themonitor 10 generally comprises a standalone device having a radiationdetector 58 (FIG. 3) directly integrated into the device to provideaudio and visual information to the responder. Alternatively, themonitor 10 may comprise a mini-computer that is configured to work witha standard external detector (not shown) that is coupled to the monitor10 via input port 40. The device may optionally have a PC interface,such as USB, serial, or other communication port 44 for programming oneor multiple devices and/or downloading or uploading stored data. Awireless receiver/transceiver may also be included in addition to, or asan alternative to, communication port 44. Additional features mayinclude a port and memory module 46, for interchangeably insertingmemory, such as a flash card (CF, SD, MS, etc.), or an audio out 48 suchas a headset jack or wireless RF transceiver for receiving the audiosignal through headphones or the like.

To protect the monitor 10 from water or other elements in hostileenvironments (e.g. firefighters, military, etc.), a transparentwaterproof casing 42 may be provided with soft button access to the modebutton 24 or other buttons may be provided. The casing 42 may also betemperature and impact resistant enclosure with a clear, magnifying(i.e., transparent) top, such that the display 14 will be magnified bythe top surface of the case 42. Case 42 may also contain an anti-glare &refection characteristics.

The housing 12 may also have attachment means, such as a belt clip, oran adjustable Velcro strap 30 for attachment to a user's wrist orforearm.

Preferably, the housing 12 may have a plastic ring slide, or similaraccess means, to allow batteries 32 to be readily replaced or recharged.Typical batteries may have a lifetime of 24 hours of continuous use, andmay be coupled to the display 14 or other indicator for signaling thestatus of the battery. The batteries may comprise a thin watch-typebattery, or a single AAA batter at one end. With a AAA battery, thehousing 12 may still maintain a slim profile, or have a larger crosssection at the end where the cylindrical battery compartment (that wouldprotrude a little beyond the plane of the device surface) would containa AAA battery.

FIG. 3 illustrates an exemplary component diagram of radiation monitor10. The monitor generally comprises a processor that is configured tosend real-time radiation data input from detector module 58 to output avisual signal at display 14 or audio output 54 via the speaker 26 orhead jack 48. The processor is also configured to input commands fromcontrols 56 used for manipulating data received from detector 58 to theformat/parameters desired by the user. The monitor 10 may have acommunications I/O 60, such as a wireless receiver, or hard-wired port44 for downloading or uploading data/control parameters. Inputted ordownloaded parameters, device instructions, detector readings, etc. mayalso be stored or accessed from the processor 50 via memory module 52.Memory module 52 may comprise ROM, SRAM or DRAM, and/or other memory,such as EEPROM, flash 46, etc.

The detector 58 may comprise any radiation measuring device currentlyknown in the art, such as a radiation sensitive pin diode or smallgiger-muller (GM) detector. A passive dosimeter strip 34 with integratedmetal filters, may be incorporated to provide a permanent record of theradiation exposure (e.g. an OSL optically stimulated luminescence stripsuch as the Luxel Dosimeter manufactured by Landauer, Inc. of GreenwoodIll.). The strip may be integrated with housing 12, and be replaced orchanged out for each different operator, or event. Films or TLD's(thermal luminescent dosimeters) may alternatively be used.

During use, the processor 50 continuously analyses the radiationintensity, as read from the detector 58, and informs the user/responderof how long he or she can remain in a radiation area before receiving apre-set maximum dose of radiation. As time passes and/or the respondermoves closer to the source of radiation and the intensity increases, theprocessor 50 will re-compute a stay time for that location based on thepre-set maximum dose and the higher dose rate. Correspondingly, theemergency responder moves further away from the source of radiation, theprocessor 50 will re-compute the stay time based on the lower dose rate.

The monitor 10 may be programmed to take readings at intervals rangingfrom more than once per second, to once every five or more seconds, etc.The frequency at which the detector takes a reading, and/or thefrequency that the display updates or refreshes, may be changedaccording to the user's expected needs, e.g. battery-life savings forlong-but-low radiation exposure environments, or rapid data exchange forenvironments that are anticipated to have a high exposure rates. Theupdate frequency may also be dynamic, e.g. automatically increasing theupdate frequency upon breaching a preset threshold dose rate or apercentage of the pre-set maximum dose.

For example, the device may take readings from the detector 58 everysecond. But because of changes in background, radiation rate, etc. thedisplay may rapidly fluctuate between values. In some situations, theresult may be an erratic display that is distracting to the user. Thus,the radiation monitor 10 may be programmed to update the displayaccording to a display time interval (DTI), i.e. the display outputremains locked even though the accumulated dose or stay time havechanged. Preferably, the DTI is programmed to change according to thepercentage of the maximum specified dose. For example, for anaccumulated dose between 0-10% of the maximum specified dose, the DTImay be specified at 5 minutes, 2 minutes between 11-50% of the maximumspecified dose, 1 minute between 51-90% of the maximum specified dose,30 seconds for over 90% of the maximum specified dose, and once persecond for 95% of the maximum specified dose. Of course, thesepercentages and rates could be varied according to the user's desiredsensitivity.

In addition, the processor may be configured to average the measureddose rates over a period of time to smooth out the display readings forstay time and dose rate. The averaging interval may also be a functionof the percentage of maximum specified dose. For example, the processormay be configured to take the average of 5 readings over 5 seconds, 10readings over 10 seconds, or 30 readings over 30 seconds, depending onthe percentage of the maximum specified dose accumulated. Because theaccumulated dose reading does not vacillate, display of the accumulateddose may always be displayed real-time. The averaging interval may beimplemented in addition to, or in place of DTI parameters. Both serve toimprove the readability of the display by avoiding rapid fluctuations ofthe stay time in low exposure and exposure rate environments.

In a referred embodiment, the computer/processor 50 may be programmed toanalyze the radiation exposure rate and compute accumulated dose, staytime and store personnel data. Before an individual enters a radiationarea, he/she is assigned a maximum permissible dose of radiation for theemergency response. This maximum dose is stored in the computer for thatindividual. When the responder enters the radiation area, the devicebegins to provide audio and visual feedback. The monitor 10 isconfigured to be individually programmed for multiple responders, sothat data for a each responder (e.g. lifetime accumulated exposure) maybe saved, transferred, or refreshed after each use.

The self-reading monitor/dosimeter of the present invention isconfigured to be programmed by a knowledgeable user (e.g. a deviceadministrator or DA) that has the responsibility to “program” the deviceresponse through the use of a simple intuitive computer interface. Theinterface allows the DA to enter the time remaining, a dose rate,cumulative dose, or a multiple of backgrounds and then select from aseries of pull down windows for the response that is desired to occur inthe event the entered condition was sensed by the monitor. The desiredunits (e.g. mrem or uSv) that are output may also be user selected.

The desired response may include any one or more of the device displayfeatures including: changing the display 14 background color (solid orflashing), displaying text (solid, flashing or scrolling) messages (e.g.entered by the DA), setting audio alarm parameters, and setting the maindisplay 14 to cumulative dose, dose rate or time remaining etc). Thisprocess may be repeated for as many conditions as the DA wanted.

FIGS. 4-9 illustrate detailed views of the display 14 readout andfunctions. The radiation monitor 10 is configured to graphically outputdigital numeric information derived from the processor 50 and detector58. The display preferably comprises one or more meters, such as uppermeter 76 and lower meter 80. The meters are configured to display thestatus of a particular reading or value set by the operator.

For example, the embodiment shown in FIG. 4 shows the bottom meter 80displaying the total radiation dose (mrem) that the operator is exposedto, and the upper meter 76 shows the current dose rate (mrem/hr)recorded by the detector. Each meter generally comprises a status bar 82showing the current dose rate or accumulative dose read by the detector.In FIG. 4, the status bars 82 indicate a dose rate of 7.6 mrem/hr and atotal accumulated dose of 3.7 mrem.

The display 14 is also configured to output a primary readout 72selected by the operator. The primary readout 72 may be any of theparameters set by the user or DA. In the embodiment of FIG. 4, theprimary readout 72 is selected as the stay time remaining, as indicatedby the primary readout identifier 74. In this case, the processor 50continuously updates the remaining stay time based on the enteredmaximum dose (illustrated by the maximum dose identifier 78), dose rateof and a total accumulated dose. For the given timeframe, the stay timeremaining is computed as:(500 mrem−3.7 mrem)/7.6 mrem/hr=65.3 hrs, or 65 hrs, 18 min.

Each subsequent update, the remaining stay time, dose rate of and totalaccumulated dose are updated to reflect new detector readings.

The primary readout 72 (e.g. stay time) is preferably output against acolored background 70 that varies color based on the status of theprimary readout. The background color may be achieved through acolor-capable display (e.g. a color LCD), or may have a coloredbacklighting, such as a series of LED's. For example, a green backgroundmay indicate stay times greater than 30 minutes, a yellow background mayindicate stay times between 30 minutes and 10 minutes, and a redbackground may indicate stay times between 10 minutes and 5 minutes.Additionally, as the stay time reaches less than 5 minutes, the redbackground may flash. The flashing frequency may also increase as thestay time lowers, e.g. less than one minute.

FIGS. 4 through 7 illustrate different possible display 14 outputs basedon varying conditions. Under the stay time intervals specified above,the display in FIG. 4 would have a green background (65 hour permissiblestay time), indicating a condition of no alarm.

As illustrated in FIG. 5, the dose rate reading is shown to havedramatically increased (2 rem/hr). Although the accumulated dose isstill relatively low (8 mrem), the rate is increased such that the staytime (14 min, 46 sec) has changed [(500 mrem−8 mrem)/2 rem/hr=0.246 hrsor 65 hrs, 14 min, 46 sec] to the second level interval, and thus thebackground color 70 is changed to yellow to indicate a moderate level ofalarm.

Now referring to FIG. 6, after a period of time at high dose rate, theaccumulated dose 80 mrem at the 3 rem/hr dose rate corresponds to an 8min, 24 sec. stay time, corresponding to a red background 70, orheightened level of alarm.

Referring now to FIG. 7, the accumulated dose of 350 mrem at the 3rem/hr dose rate corresponds to only a 3 min permissible stay time giventhe 500 mrem maximum dose, and thus the red background 70 would beflashing or blinking to indicate extreme alarm.

It will be appreciated that the foregoing time categories and periodsare non-limiting, and that the radiation monitor 10 may be programmed tohave other time categories and periods. In other words, the times forswitching from green to yellow, from yellow to red, and from red toflashing red are completely programmable based on, for example, thetotal dose that could be sustained by the responder taking into accountsuch things as departmental policy on maximum allowed dose and priorexposure to radiation. In addition, other colors e.g. blue, orange, etc,may be used in addition to or as an alternative to the above describedcolor set.

The display 14 may be set to update the stay time at varying intervalsand varying modes of display, such as, dose rate, cumulative dose, staytime, etc. Display options include varying background colors andthreshold values for color changes with stay time. In other words, thedevice can be switched from a “stay time mode” to a mode thatillustrates the primary readout 72 to conventional units of dose rate(as shown in FIG. 8) and cumulative dose (as shown in FIG. 9. Of course,it will be appreciated that the radiation monitor 10 can be configuredto change background color based intervals of dose rate, cumulativedose, or any other parameter set by the user.

Referring now to FIG. 10, radiation monitor 100 may alternatively beequipped with a display 14 having a monochrome background 70. In thisconfiguration, the background 70 color would remain the same, and aseries of indicators 90, 92, and 94 may be used to display status orwarnings according to the above mentioned stay time ranges. Each of theindicators may have a colored LED, or other illumination source, thatilluminates according to the current calculated stay time. For example,for a stay time over 30 minutes, the first LED 90, having a green color,would illuminate, while the second LED 92 and third LED 94 remain unlit.For a stay time between 30 min and 10 min, the second LED 92, having ayellow color, would illuminate. For a stay time between 10 min and 5min, the third LED 94, having a red color would illuminate. The thirdLED 94 could also flash for a stay time lower than one minute.Generally, only one LED would normally be illuminated at one time,except during a “notice alarm” when it is desired to draw the wearer'sattention to new text is being displayed. In this case both the greenand yellow LED may flash simultaneously.

Each of the LED indicators 90, 92, 94 may also have a different shape,boarder and distinctive positions on the monitor. Thus, the position andcorresponding shape and boarder of the illuminated alarm help the wearerto distinguish which of the alarms is activated. For example acolor-blind person could use these other features (position, shape andboarder) to figure out which alarm had been activated.

FIG. 10 also illustrates use of a monitor 100 having a cursor typebutton 96 for moving left-right, up-down along menu options.

Furthermore, the device is optionally equipped with an audio speaker 26as well as an audio out 48 such as a headset jack, or RF audio outputtransmitter for wireless responder headsets and incident control centertelemetry. The audio out 48 allows the responder to receive vitalinformation in low light or smoke filled environments where it would bedifficult to read the meter display. The radiation monitor is configuredto change the tone, sound, or frequency of the audio signal based on thestatus of a particular parameter. For example, for a calculated staytime above 30 min, the audible tone alarm may be off. When the stay timefalls in the range between 30 minutes and 10 minutes, the tone may alarmat a rate of once every 10 seconds, once every three seconds for a staytime of 10 minutes to 5 minutes, and once every half second for a staytime below 5 minutes. Optionally, information can be sent to a wirelesstelemetry receiver for central monitoring of the radiation exposureinformation.

The radiation monitor 10 may also be programmed to display a particularpre-programmed message 116 (see FIG. 11) upon determination of aparticular event or threshold exposure level. For example at 100 mrem/hrthe device may be selected to flash yellow and display the scrollingmessage “Exposure rate exceeds 100 mrem/hr . . . . Notify command postand report your location).” Another example may be when a cumulativedose of 10 rem is reached the detector may turn red and display themessage “One-half of maximum dose reached, prepare to return to controlpoint,” or “One-half of maximum dose reached . . . . Notify command postand engage only in immediate life saving activities.” These messages maydisplay at the region of the primary readout, and may alternate with thereadout while the condition is still present.

The pre-programmed text messages may also be transmitted via an audiosignal, e.g. through a pre-recorded voice or computer generated audiomessage. These audio messages may be transmitted in addition to, or asan alternative to, a visual text message.

FIG. 11 shows an alternative display readout, which may be used oneither monitor 10 or 100. In this embodiment, the status meters arereplaced by numeric indicators 112 and 114, if so desired by the user.The pre-programmed text message 116 is also displayed prominently alongthe bottom of display 14.

The radiation monitor 10 may also have the capability to measure andcalculate an “average background,” i.e. ambient radiation level, withthe push of any of the control buttons (e.g. holding down the “mode”button 24. For example, the “average background” would be derived froman average or median dosage rate at entry into a target area. Theradiation background is then stored in memory, and continually comparedagainst the subsequent dose rate at each update.

This feature may be used, for example, in a higher than normal radiationbackground area in which one is trying to locate focal hot spots, orlarge deltas in radiation exposure rate, in the contaminated area. Forexample, the radiation monitor 10 may be programmed by the DA to averagethe new background for a given period of time (e.g., 5 minutes). Thenthe device will report (alarm) by one or more of the selected methods(e.g., color, alarm, audio message, text), etc when radiation exposurelevels reach administrator selected multiples of the new averagebackground (e.g., 10, 50, and 100 times background). These levels (i.e.,conditions), having been previously associated with one or more givendevice actions, will have a corresponding alarm indicator. For examplethe average background in the contaminated area may be 2 mrem/hr (e.g.,approximately 40 times higher than normal background). When the devicedetects a field of 20 mR/hr (i.e., 10 times the newly acquiredbackground), the detector may start to flash green at one secondinterval and display a scrolling message (previously input by the deviceadministrator) “Hot spot detected at >20 mR/hr. Notify command post ofyour current location.”

Referring now to FIGS. 12 and 13, an exemplary context sensitive PC pulldown menu in accordance with the present invention is illustrated. Asshown in FIG. 12, the display 12 may show a series of programmableconditions 120. Each condition box 120 each has a pull-down menu 132(see FIG. 13) of different radiation exposure criteria to select from.Each condition will also have a value box 122 and correspondingpull-down 134. The value selected at box 122 will determine when thespecified secondary signal identified in the action 1 box 124 andcorresponding pull-down 136. The value 1 box 126 may further specify theaction to be communicated, e.g. illuminate a red, yellow or greendisplay. In addition, a tertiary signal can be defined (e.g. textmessage, audio signal, etc.) with the action 2 box 128 and correspondingpull-down 140. The tertiary signal may be further qualified with thevalue 2 box 130 and associated pull-down 142. If necessary, additionalsignals may also be assigned to occur on a given condition.

In one embodiment, the radiation monitor could house an imbedded GPSreceiver that would allow the coordinates to be logged in the device andsaved or transmitted to a command post. This data could then be used tomap a particular area, or even provide a contoured map of exposure ratessimilar to that illustrated in topographical geographic maps. This couldalso be accomplished indoors with existing technology such as an imposedlaser grid system.

The device may further include a training mode using RFID technologythat allows the user to simulate the presence of radiation (withoutactual exposure to radiation) using an RF signal. Generally, radiationmonitor 10 or 100 may be coupled with a RF receiver (not shown) that iseither integrated into the device, or coupled to the processor 50 viainput port 40 or communications port 44. An RFID tag would be placed ina training area to simulate a radiation source. The inverse square lawbehavior of the RF signal will simulate ionizing radiation exposure. Asthe location of the monitor 10/100 nears the location of the RFID tag,the received RF signal will intensify in much the same way as aradiation source. Correspondingly, the unit display will respond in thesame way as in the normal operating mode except that the words “trainingmode” will be prominently displayed

Although the description above contains many details, these should notbe construed as limiting the scope of the invention but as merelyproviding illustrations of some of the presently preferred embodimentsof this invention. Therefore, it will be appreciated that the scope ofthe present invention fully encompasses other embodiments which maybecome obvious to those skilled in the art, and that the scope of thepresent invention is accordingly to be limited by nothing other than theappended claims, in which reference to an element in the singular is notintended to mean “one and only one” unless explicitly so stated, butrather “one or more.” All structural, chemical, and functionalequivalents to the elements of the above-described preferred embodimentthat are known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe present claims. Moreover, it is not necessary for a device or methodto address each and every problem sought to be solved by the presentinvention, for it to be encompassed by the present claims. Furthermore,no element, component, or method step in the present disclosure isintended to be dedicated to the public regardless of whether theelement, component, or method step is explicitly recited in the claims.No claim element herein is to be construed under the provisions of 35U.S.C. 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for.”

1. A personal radiation monitor, comprising: a processor responsive to aradiation detector; said radiation detector configured to produce realtime radiation exposure data; said processor configured for calculatingone or more characteristics of an individual's radiation exposure; saidprocessor further configured to continuously recalculate said radiationexposure data to update the one or more radiation exposurecharacteristics; and a display responsive to information provided bysaid processor, said display adapted to display at least one of said ormore radiation exposure characteristics as a primary signal from saidprocessor; said processor further configured to transmit a secondarysignal to said individual; said secondary signal correlating to a rangeof values of one of said one or more radiation exposure characteristics;wherein at least a portion of said display is configured to change colorupon one of said one or more radiation exposure characteristicsexceeding a threshold limit outside said range of values; wherein saiddisplay is configured to illuminate a first color upon a radiationexposure characteristic falling within a first range of values, and asecond color upon a radiation exposure characteristic falling within asecond range of values; wherein said one or more radiation exposurecharacteristics further comprise a stay time based on the individual'smaximum permissible radiation dose limit; wherein said processor isfurther configured for periodically recalculating said stay time;wherein update frequency of the recalculation is a function of one ormore of the radiation exposure characteristics; wherein said processoris configured to output said stay time to the display at a display timeinterval; and wherein said display time interval locks the value of thedisplay for a specified period of time.
 2. A radiation monitor asrecited in claim 1, wherein said display is configured to illuminate athird color upon a radiation exposure characteristic falling within athird range of values.
 3. A radiation monitor as recited in claim 2,wherein the display is configured to flash the third color upon aradiation exposure characteristic falling within a fourth range ofvalues.
 4. A radiation monitor as recited in claim 1, furthercomprising: one or more illumination sources in proximity to saiddisplay; wherein said one or more illumination sources are responsive tosaid secondary signal so as to communicate one or more radiationexposure characteristics exceeding a threshold limit outside said rangeof values.
 5. A radiation monitor as recited in claim 1: wherein saidprocessor is further configured to transmit a tertiary signal to saidindividual; wherein said tertiary signal comprises an audio signalhaving a rate associated with said range of values; and wherein saidaudio signal rate is configured to change upon one of said one or moreradiation exposure characteristics exceeding a threshold limit outsidesaid range of values.
 6. A radiation monitor as recited in claim 1,wherein said one or more radiation exposure characteristics comprise anaccumulative radiation exposure level.
 7. A radiation monitor as recitedin claim 1, wherein said one or more radiation exposure characteristicsfurther comprise a radiation dose rate.
 8. A radiation monitor asrecited in claim 1, wherein said processor is configured to average theradiation dose rate over a period of time to stabilize the display ofthe stay time in fluctuating radiation exposure environments.
 9. Aradiation monitor as recited in claim 1, wherein at least a portion ofthe display changes color when the stay time exceeds a threshold limitoutside said range of values.
 10. A radiation monitor as recited inclaim 1, wherein the display is configured to simultaneously display twoor more of radiation exposure characteristics comprising: radiation doserate, accumulative dose, or stay time simultaneously.
 11. A radiationmonitor as recited in claim 10, wherein the accumulative dose isdisplayed as a percentage of the individual's maximum permissibleradiation dose limit.
 12. A radiation monitor as recited in claim 10,further comprising: a plurality of controls coupled to the processor;wherein the controls are configured to allow the primary readout to betoggled between the one or more radiation exposure characteristics. 13.A radiation monitor as recited in claim 1, wherein the display isconfigured to display one of the one or more radiation exposurecharacteristics as a primary readout.
 14. A radiation monitor as recitedin claim 13, wherein one or more of the remaining radiation exposurecharacteristics are simultaneously displayed on a status meter.
 15. Aradiation monitor as recited in claim 1, wherein the display is furtherconfigured to transmit a pre-programmed message upon a specifiedradiation exposure characteristic value.
 16. A personal radiationmonitor, comprising: a processor responsive to a radiation detector;said radiation detector configured to produce real time radiationexposure data; said processor configured for calculating one or morecharacteristics of an individual's radiation exposure; said processorfurther configured to continuously recalculate said radiation exposuredata to update the one or more radiation exposure characteristics; and adisplay responsive to information provided by said processor, saiddisplay adapted to display at least one of said or more radiationexposure characteristics as a primary signal from said processor; and aplurality of indicators in proximity to the display; each of saidplurality of indicators having a unique shape with respect to eachother; said processor further configured to transmit a secondary signalto said individual; said secondary signal correlating to a range ofvalues of one of said one or more radiation exposure characteristics;wherein one of the plurality of indicators is configured to illuminatesaid secondary signal upon one of said one or more radiation exposurecharacteristics exceeding a threshold limit outside said range ofvalues; and wherein a first indicator of the plurality of indicators isconfigured to illuminate upon a radiation exposure characteristicfalling within a first range of values, and a second indicator of theplurality of indicators is configured to illuminate upon a radiationexposure characteristic falling within a second range of values.
 17. Aradiation monitor as recited in claim 16, further comprising: a thirdindicator configured to illuminate configured to illuminate upon aradiation exposure characteristic falling within a third range ofvalues.
 18. A radiation monitor as recited in claim 17: wherein thefirst indicator is spaced apart from the second indicator at a firstdistance, and the third indicator is spaced apart from the secondindicator at a second distance; and wherein the first distance isdifferent than the second distance to aid in distinguishing whichindicator has been illuminated.
 19. A radiation monitor as recited inclaim 16, wherein each of the indicators illuminates a unique color. 20.A radiation monitor as recited in claim 19, wherein a portion of thedisplay is configured to simultaneously illuminate a color similar tothe illuminated indicator color.
 21. A radiation monitor as recited inclaim 16, wherein each of the indicators comprises an LED positionedwithin a distinctively shaped border.
 22. A radiation monitor as recitedin claim 16, wherein said one or more radiation exposure characteristicscomprise an accumulative radiation exposure level.
 23. A radiationmonitor as recited in claim 22, wherein said one or more radiationexposure characteristics further comprise a radiation dose rate.
 24. Aradiation monitor as recited in claim 23, wherein said one or moreradiation exposure characteristics further comprise a stay time based onthe individual's maximum permissible radiation dose limit, saidprocessor further configured for continuously recalculating said staytime.
 25. A personal radiation monitor, comprising: a processorresponsive to a radiation detector; said radiation detector configuredto produce real time radiation exposure data; said processor configuredfor calculating one or more characteristics of an individual's radiationexposure; said processor further configured to continuously recalculatesaid radiation exposure data to update the one or more radiationexposure characteristics; a display responsive to information providedby said processor, said display adapted to display at least one of saidor more radiation exposure characteristics from said processor; and aGPS receiver coupled to the processor; wherein coordinate readings fromthe GPS receiver are configured to be logged to provide a radiationexposure characteristic reading to a particular location.
 26. A personalradiation monitor as recited in claim 25, wherein the GPS receiverreadings are configured to provide a radiation exposure characteristicmap of a particular area.
 27. A personal radiation monitor as recited inclaim 26, wherein the map comprises a contoured map of exposure rates.